Lung function and airway responsiveness in children and adolescents after hyaline membrane disease: a matched cohort study.

Some investigators consider prematurity to be responsible for the lung function abnormalities found in prematurely born children and adolescents who had neonatal respiratory diseases. This study attempts to measure the effect of neonatal respiratory disease on lung function during school age and adolescence, by controlling the confounding effect due to prematurity. Lung volumes, airway resistance and specific airway conductance measured by plethysmography, maximum expiratory flow-volume curves, pulmonary diffusion of carbon monoxide, and the airway responsiveness to a challenge with methacholine, were determined in a cohort of children aged 8-14 yrs, who had suffered from hyaline membrane disease but who did not develop bronchopulmonary dysplasia. The values obtained were compared with those of children without hyaline membrane disease, not ventilated for other causes, and matched for gestational age, sex and age. Thirty six pairs of children were enrolled, of which 26 participated in the methacholine test. Compared to their paired controls, children with hyaline membrane disease had a significantly lower forced expiratory volume in one second (FEV1), forced mid-expiratory flow (FEF25-75), and maximal expiratory flow when 75, 50 and 25% of the forced vital capacity remained in the lung (MEF75, MEF50 and MEF25, respectively), and a significantly higher airway resistance (Raw). The effect was less in children born more prematurely, who showed less difference in FEF25-75, MEF75 and MEF25. The duration of treatment with steroids in the neonatal period was associated with a reduction in the differences in FEV1, MEF25 and Raw. Independent of prematurity, hyaline membrane disease and its treatment is associated with alterations in long-term lung function, even in children who do not develop bronchopulmonary dysplasia. The effect can be less in more premature children, and neonatal steroids can have a long-term preventive effect.